ASoC: wm_adsp: Fix halo scratch register reading.

ASoC: wm_adsp: Fix halo scratch register reading.

Halo register addresses increment by 8 instead of the usual 4. Read
sequential scratch registers accordingly.

MOT-CRs-fixed: (CR)
Signed-off-by: James Bodzay <jbodzay@opensource.cirrus.com>
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Change-Id: I88294fa44ba1748b5127824b708bbbf8122dcfc8
Reviewed-on: https://gerrit.mot.com/1383853
SLTApproved: Slta Waiver
SME-Granted: SME Approvals Granted
Submit-Approved: Jira Key
Tested-by: Jira Key
Reviewed-by: Zhengming Yao <yaozm1@mt.com>